The Best Dive Sites in the Similan and Surin National Parks

Nestled in the Andaman Sea off the west coast of Thailand, about 40 miles northwest of Phuket, you’ll find the Mu Ko Similan and Surin National Parks, some of the country’s best dive destinations.

Established in 1982, the Mu Ko, which means “group of islands,” Similan Islands National Park encompasses an archipelago of 11 islands. Thailand established the five islands of the Surin archipelago, on the oceanic border of Myanmar, as a national park in 1981.

While 90 percent of the coral life here died out following water-temperature changes in 1998 and 2010, marine life is returning to these islands. The Similans especially offer diversity, ranging from nudibranchs and pipefish to manta rays and whale sharks. Water temperatures range from 80 F to 84 F (27 C to 29 C), so a 3 mm shorty should work for most divers. The best way to see these sites is by liveaboard, although day-trips are available. Here, in no particular order, are five of the best dive sites in the Similan and Surin National Parks.

West of Eden, Similan Islands National Park

West of Eden runs from the northwest side of Island No. 7 to its northern tip, where it blends into another famous Similan dive site, Deep Six. Entering the water on the west side of the island, divers will descend into a garden of coral bommies, or outcroppings. At around 30 to 40 feet (10 to 12 m), schools of angelfish and snapper circulate among the hard and soft corals. Spiny lobsters are lurking in holes and clownfish are aggressively defending their homes.

Divers can cruise between the granite walls and channels and head a little deeper to around 82 to 90 feet (25 to 28 m), where stunning, large gorgonian fans dot the walls. Deeper among the granite and coral channels, watch for spearing mantis shrimp hiding in their homes, ribbon eels lurking in crevices, moray eels, small banded pipefish and hordes of Durban dancing shrimp. As you begin to shallow up, watch for barracuda passing overhead or a curious turtle swimming by. This is a great lunchtime or afternoon dive as the sun shines through the water on the west of the island, bringing the colors to life. It’s suitable for divers from beginners to advanced.

Elephant Head Rock, Similan Islands National Park

From the surface, this dive site looks like the semi-submerged head of a giant elephant swimming along, complete with nostrils. Because it’s a pinnacle in open water between Similan Islands No.7 and No.8, it’s sometimes subject to strong currents, so pay attention to your briefing and guide. A maze of swirling granite boulders, channels and swim-throughs awaits at depths between 40 and 100 feet (12 to 30 m).

You’ll most commonly visit this site via liveaboard, dropping in on the south side. When entering the water, descend with your group as soon as possible so as not to drift past the site. Follow your guide and take shelter close to the rocks. Then, pause and look around at the stunning view of an underwater town made of granite boulders, crests and valleys, all covered with gorgonian fans. You may find curious peacock mantis shrimp, moray eels and lionfish lurking in the holes.

Begin heading east and look out of a channel in the rock at 60 feet (18 m). Drift down the channel like Luke Skywalker negotiating the Death Star in “Star Wars,” and watch for the face-sized hole in the granite on your right; it makes for a great photo opportunity. Watch your buoyancy as you head through caverns. Moving deeper as you exit the center of the site, you may find a seamoth inching over the rock face. In the deeper blue you may see a shark or two circling beneath you, or a bed of bluespotted stingrays hiding in the sand. This site too makes for a great early morning dive as all the life is waking up. The site’s location makes it a challenge and it’s best suited to advanced or intermediate divers.

Koh Bon West, Similan Islands National Park

Koh Bon is known for frequent seasonal manta-ray sightings. Currents at Koh Bon can vary from negligible to strong, so pay attention to your guide. Entering the water on the south side of the island, bring yourself in close to the wall on your right shoulder as you begin to head west. The wall is coated with patches of blue, yellow and purple soft coral. The cracked limestone walls create homes for pipefish, banded coral shrimp and nudibranchs. Divers can sometimes spot Maldivian sponge snails as well. As you approach the ridge, be aware of currents and look for cues from your guide. Keep an eye to the blue as well, though, as something big, such as a whale shark, may be passing by. This makes for a great mid-morning or late-afternoon dive, as that’s when mantas come in to feed and clean.

Koh Tachai Pinnacle, Similan Islands National Park

Although, sadly, the beautiful island of Koh Tachai itself has been closed to tourists, the offshore Koh Tachai Pinnacle — off the southern corner of the island away from coast — remains open to divers visiting the marine park. A favorite of the local guides for its challenges, Tachai Pinnacle is at the northern tip of the Similan Islands Park, around two hours north of Koh Bon. Sometimes known as “The Dome of Doom” because of currents, Koh Tachai Pinnacle can be a fickle site. It’s best suited to intermediate and advanced divers.

Enter the water and be prepared to descend as quickly as possible. Open-ocean pinnacles are not the place to delay at the surface, cleaning your mask or adjusting your camera. Descend onto the dome to between 45 and 100 feet (14 and 30 m), following your guide, to take shelter from currents. The south and east sides feature barracuda swirling around the sprawling granite rocks; the west and north sides are covered in beautiful coral gardens. Keep your eyes peeled for hunting trevally above and manta and whale shark sightings. There are two other pinnacles slightly to the north, which feature some of the most beautiful corals in Thailand.

Richelieu Rock, Surin Islands National Park

Probably Thailand’s most famous dive site, Richelieu Rock is about 11 miles east of Ko Surin. Covered with coral and life, as on Koh Tachai Pinnacle, the conditions here can vary. Depths range from 40 to 100 feet (12 to 30 m). Because it’s another open-ocean site, it’s best suited to intermediate and advanced divers. Photographers looking for intricate shots will be in heaven here.

Divers will typically enter the water on the southwest corner of this horse-shoe-shaped pinnacle, and follow the guide either inside the rock’s shape for shelter or along the east side of the pinnacle. Life coats Richelieu Rock, so take your time looking for smaller critters. You may find a tiger-tail seahorse, harlequin shrimp or ghost pipefish. You’ll often see resident pharaoh cuttlefish mating here, flickering as they change color to impress their mate. Above, barracuda hang in the currents like nightclub bouncers overseeing their territory.

From October to May, but particularly from mid-January to mid-March, there can be whale shark sightings at Richelieu. These giant fish feed by filtering the rich water around the rock, so keep an eye on the blue. Although it’s a great dive any time of day, Richelieu can get very busy due to its popularity. Visit in the early morning or at sunset for the best experience.

By guest author Marcus Knight (The Scuba Monkey)